This is a proposal to create a biologically active prosthetic arterial graft incorporating gene silencing to an antithrombotic and pro-angiogenic surface. The research team is unique in its cohesiveness and breadth of expertise including textiles, polymers, cell biology, molecular biology, and surgery, all with an established focus on vascular grafts. This project builds on our long-standing work where we have 1) characterized the lesion of anastomotic neointimal hyperplasia (AIH) downstream of the prosthetic graft, 2) established the role of blood flow-surface interaction in AIH pathogenesis, 3) applied biologic modification to the graft surface by incorporating antithrombotic (rHirudin) and endothelial cell growth factor (VEGF) to delay thrombus formation and improve endothelialization, and 4) determined the unique gene signature associated with AIH development, including identification of high profile pathogenic targets. The goals of the current proposal are to 1) Validate the involvement of MARCKS, CDH11, and TSP2 in the pathogenesis of AIH, by means of in vitro loss-of-function studies in endothelial and smooth muscle cells using siRNA, 2) Create a bioactive electrospun nanofibrous graft material and determine optimal physical properties that it requires for effective siRNA delivery to the vasculature under pulsatile flow and operating room conditions and, 3) implant the graft prototype in a large canine animal model, after preliminary testing in a rat model, and determine sequentially its potential to deliver siRNA, effectively induce gene silencing and positively impact the development of AIH lesions, including graft healing and patency. This is a stepwise study bringing to bear a unique and appropriately broad range of expertise on the effective application of gene silencing to improve the outcome of prosthetic arterial grafts. The information will also be of interest in the larger use of materials to deliver siRNA for therapeutic purposes.